Thursday, September 26, 2013

An area of showers and scattered thunderstorms over the western RRV pushed north across Winnipeg late this morning, bringing about 5.5 mm of rain to Winnipeg airport through midday. It wasn't much, but it was the most significant rainfall in the city since August 18th when 30 mm fell during a thunderstorm. Today's rainfall brought the monthly total to 10.5 mm at YWG airport, still well below the normal September rainfall of 45.5 mm (1981-2010 average)

Regardless, the rain was welcome, and we could be in for some more rain Friday into Saturday as a stationary frontal system sets up along the MB/Ontario border, with a couple waves of rain spreading north along the boundary. At this point, it looks like the bulk of the heaviest rain will be over SE Manitoba into Lake of the Woods/NW Ontario where 25-50 mm of rain is possible by Saturday evening. (see image left) Amounts will be less over Winnipeg and the RRV, with a sharp dropoff in rain amounts west of the RRV. For Winnipeg, rainfall amounts of 5-10 mm are possible Friday afternoon into Saturday morning with higher amounts expected east of the city. However, if the rain shield edges further west as some models have been suggesting, Winnipeg could also see higher amounts.

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First batch of showers pushing through southern MB now, mainly over SE MB, and looks like we should be fairly dry the rest of the day through this evening. Next wave of rain develops over the eastern Dakotas tonight and spreads north into southern MB overnight into Saturday. Latest RGEM guidance has shifted rain area a bit further west, now showing about 20 mm into Winnipeg overnight through midday Saturday, while NAM is also showing about 20 mm in Winnipeg. Those amounts may be a little overdone for the city, but I think it points to a more likely scenario that we'll see some measurable rain from the next wave of precip moving up tonight. Current forecast of 60% POP for Winnipeg today, tonight and tomorrow doesn't adequately explain the best rain chances over the next 36 hours.

Up to 14 mm at my place as of 1030 am, and we still have a few hours of rain to go. Likely will be approaching 20 mm by the time it tapers off this afternoon. Sprague is the big winner with at least 35 mm so far today on top of the 50 mm they got yesterday. They could end up with 2 day total around 100 mm by the time it's over.

Up to 20 mm as of 2 pm at my place and still raining, although back edge of rain is approaching from the west.. so rain should be tapering off in Winnipeg over the next hour or two. I've updated the blog entry with rainfall amounts since midnight up to 1 pm.. generally 15-20 mm in the RRV so far including Winnipeg, with 20-40 mm over SE MB. Big winner is Sprague with another 39 mm today, and 88 mm since yesterday morning.

Rainfall totals updated to 7 pm.. pretty much done now. Generally 20-25 mm in Winnipeg today.. 10-30 mm over the RRV (less west, more east) and 25-50 mm over SE MB. Sprague had 45 mm today and a total of 95 mm since yesterday morning. Overall, a well needed long soaking rain for Winnipeg/RRV and SE MB..

Now we get to end the weekend with a beautiful Sunday.. lots of sunshine, and gusty southerly winds of 30 gusting 50 km/h pushing us back to the 20-21C mark.. nice day to dry up after today's rain.

A couple nice days to finish up our September.. mainly sunny today with gusty south winds taking us back to the low 20s this afternoon, and then not as windy tomorrow with sun and clouds, and highs around 23C. Current forecast for Winnipeg calling for a 40% chance of showers tomorrow afternoon but guidance suggests precip threat won't be until the evening after sunset.

September should finish with a monthly average around 15C.. a good 2-3C above normal.